hammond



J. H. HAMMOND, JR.

SYSTEM OF ACOUSTIC SIGNALING.

- APPLICATION FILED JUNE 10. 1912. RENEWED MAR. 18.1919.

1 320 6860 Patented Nov. 4, 1919.

2 SHEETS-SHEET I.

- l/VVE/VTOR J. H. HAMIVIO ND, JR. SYSTEM OF AQOUSTIC SIGNALING. APPLICQXTIONflLED JUNE 10, I912. RENEWED MAR. M11919.

1 320586, Patented N0v.'4,1919.

2 SHEETS SHEET 2.

WITNESSES I I II IIl/ENTOR ww fi atom HAYS HAMMOND, JR, GLOUCESTER, MASSACHUSETTS.

SYSTEM OF ACOUSTIC SIGNALING Specification of Letters Patent.

. Patented Nov. 4, 1919.

Application filed June 10, 1912,'Serial No. 702,728. Renewed March 18v, 1919. Serial 1V0. 283,444.

To all whom it may concern Be it known that I, J OHN HAYS HAMMO D, Jr., a citizen of the United States, residing at Gloucester, in the State of Massachusetts, have invented certain new and useful Ianprovements in Systems of Acoustic Signalin of which the following is a specification.

Referring to the accompanying drawin s:

igure 1 shows my acoustic telegraph system with an alternating current generator.

Fig. 2 shows my acoustic telegraph system with a variable-pitch buzzer.

Fig. 3 shows my acoustic telegraph system with a telephone transmitter and a variable-pitch buzzer, as applied to present day telephone systems' Fig. 4 shows my system of acoustic signalg adapted to wireless telephone transmittin and receiving stations. I

ig. 5 shows my system of acoustic signaling adapted to a wireless .transmittiu station using an electric are as an oscil atory current generator,

Fig. 6 shows a number of difi'erent characters such as can beused with my system.

If I desire to telegraph shorthand characters by the use of acoustic tones of varying pitch, I take transmitter capable of producing tones ranging in frequency, say,

from 200 to 500 per second, and capable of changing the frequency within these limits as quickly or as slowly as may bedesired.

'0 Then if a character such as that shown at, a,

erator as the character shown at a. distance between the: horizontal lines 1, 1

Fig. 6, is to be sent, the transmitting apparatus' must be started at the frequency ofv 200 per second, mad to rise to 500 persecond as quickly as possible, and then cutoff. At the receiving end the signal will then be heard as a sound of rapidly increasing pitch from 200 to 500 periods per second, and may be graphically recorded by the op- The second, raised slowly at first and then faster and faster until a frequency of 500 per second is reached, when it is cut off. The rest of the characters shown in Fi 6, as well as any number of others can sent and re; ceived by my system. The difference in pitch or in intensity, corresponding to the distance between the horizontal lines 1, 1 and 2, 2, can be made anything that is convenient.

In Fig. 1, an alternating current generator G is mechanically connected to an electric motor M, the speed of which is controlled by a variable resistance I connected in circuit with a battery B. A movable switch arm J, in which is a key K, travels over the variable resistance I, and when the key K is closed the 'circuit through the motor M is completed and the generator G is, started. The generator G is inductively connected with the line wires F. and F by means of the step-up transformer D D and the line wires lead to a receiving telephone B. When key K is closed and switch arm J is moved over resistance I, the speed of motor M is made to change, and therefore the frequency of generator G is varied, and alternating currents are sent over the line F F producing:

I thumb-screw Sis turned the tension of wire an acoustic tone in receiving telephone R,

the pitch of which tone is dependent upon the position of switch arm J.

battery B ythe primary D of'step-up transformer D D and contact X. An armature N is attached to a wire W which isfixed at Q and Pin such a way that when the W- is varied, and its rate of vibration is changed. The contact at X with the block I disenga d by the action of, the compression supportgig the'thumb-screw S is normally spring is prevented from-rising too far by the stop .Z. By-pre'ssing the thumb-screw S and end support P. downward so as to make contact at X, the buzzer circuit will be closed and the armature N will be attracted by electromargnet N, thus breaking the circuit, which will be immediately closed again, and" this making and breaking of the circuit will proceed at a rate depending upon the rate of vibration of the wire W, which Vibration rate is dependent upon the tension of the'wire. These curreut'changes in primary'D will induce corresponding changes in secondary D and hence in the line F F and receiving:

telephone R By turning the screw S, the rate of vibration of the wire W is changed andcorresponding acoustic tones are heard at receiving telephone R In Fig. 3, V is a variable-pitch buzzer. energized by battery'B and controlled by thumb-screw S said buzzer impressing sound waves on telephone transmitter T,

which is in circuit with battery B and priligary D of induction coil D D the secondary D being in circuit with line F F and receiving telephone R .v By varying the adjustment'of buzzer V,tones of varying pitch, corresponding to different characters, are sent over the line to the receiver R In Fig. 4, a high-frequency alternator H energizes antenna A through coupling coils' L and L Antenna A'is connected in any suitable way with the 'microphone trans- 'mitter T and is grounded at E. A variablepitch buzzer V is energized by battery B? and controlled by thumb-screw S and said buzzer impresses sound waves uponmicro- '3 phonesT thus impressing amplitude variations upon the electric waves radiated from antennaA. The receiving antenna A is in circuit with the tuning 0011 L and the variable condenser C, and is groundedat E Said antenna is inductively coupled to the closed oscillatory circuit L 0 consisting of coil L and condenser G which. circuit' supplies unidirectional currents to receiving In F ig; 5, an oscillatory are 0 is supplied 7 from-a. source of direct current B through I the choking coils U and U An oscillatory circuit, containing the-condenser C and the inductance coil L, is shunted around the arc and is inductivelyv coupled to the antenna A by means 6f the coil L The values of capacity. C and inductance L are such that high-frequency oscillatory currents will be waves of a I suitable frequency will be radiated from A Around the arc 0 there is also shunted another oscillatory circuit containing the variable condenser C the key K and the coil L. ductance L have such values that in their circuit there will be produced oscillatory currents of frequencies within the limits of audibility. When the key K is closed and the value of capacity C? is varied amplitude variation corresponding to audible tones will be impressed uponthe waves radiated from antenna A A receiving apparatus similar to that of 'Fig. 4 can be used with this transmitting apparatus, and as the ca- Capacity C and inand the end support P of the wire produced in the circuit, such that electric pacity C is varied, correspondingly varying acoustic tones willbe heard in telephone.

I claim as'my invention 1 1. A method of. electric si aling in I which characters are indicated a:

with respect to a predetermined note at different rates ofjspeed to indicate the form of the characters to be reproduced.

2. A'method ofelectricsignaling in which characters are indicated by acoustic tones which consists in changing the pitch at a varying rate to indicate a curvilinear character. I

3 A method of electric wave signaling in .wluch characters are indicated by acoustic the receiving I acoustic tones, which consists 1n changing the pitch tones, which consists in changing the pitch with respect to a predetermined note at different rates of speed to indicate the form of thecharacters to be reproduced.

A. A method of electric wave signaling i samees 6. A code for signaling by sound waves in which various characters are indicated respectively by transmitting acoustic tones and varying the pitch of said tones at various predetermined rates.

7. A code for signaling by sound Waves in which various predetermined characters are indicated respectively by predetermined changes in the pitch of acoustic tones and by predetermined variations in the rates of 10 eflecting said changes.

This specification signed and witnessed this 22nd day of May A. D. 1912.

7 JOHN HAYS HAMMOND, JR. 

